package com.hjc.herol.util;

import java.lang.reflect.Type;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import java.util.Map;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
import com.google.gson.JsonPrimitive;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;

/** 
* Gson类库的封装工具类，专门负责解析json数据</br> 
* 内部实现了Gson对象的单例 
* @author fuyzh
* @version 1.0 
* @since 2012-9-18 
*/  
public class JsonUtils {  
  
    private static Gson gson = null;  
      
    static {  
        if (gson == null) {  
            gson = new Gson();  
        }  
    }  
  
    private JsonUtils() {  
      
    }  
  
    /** 
     * 将对象转换成json格式 
     * @author fuyzh
     * @param ts 
     * @return 
     */  
    public static String objectToJson(Object ts) {  
        String jsonStr = null;  
        if (gson != null) {  
            jsonStr = gson.toJson(ts);  
        }  
        return jsonStr;  
    }  
  
    /** 
     * 将对象转换成json格式(并自定义日期格式) 
     * @author fuyzh
     * @param ts 
     * @return 
     */  
    public static String objectToJsonDateSerializer(Object ts,  
            final String dateformat) {  
        String jsonStr = null;  
        gson = new GsonBuilder()  
                .registerTypeHierarchyAdapter(Date.class,  
                        new JsonSerializer<Date>() {  
                            public JsonElement serialize(Date src,  
                                    Type typeOfSrc,  
                                    JsonSerializationContext context) {  
                                SimpleDateFormat format = new SimpleDateFormat(  
                                        dateformat);  
                                return new JsonPrimitive(format.format(src));  
                            }  
                        }).setDateFormat(dateformat).create();  
        if (gson != null) {  
            jsonStr = gson.toJson(ts);  
        }  
        return jsonStr;  
    }  
  
    /** 
     * 将json格式转换成list对象 
     * @author fuyzh 
     * @param jsonStr 
     * @return 
     */  
    public static List<?> jsonToList(String jsonStr) {  
        List<?> objList = null;  
        if (gson != null) {  
            java.lang.reflect.Type type = new com.google.gson.reflect.TypeToken<List<?>>() {  
            }.getType();  
            objList = gson.fromJson(jsonStr, type);  
        }  
        return objList;  
    }  
      
    /** 
     * 将json格式转换成list对象，并准确指定类型 
     * @author fuyzh
     * @param jsonStr 
     * @param type 
     * @return 
     */  
    public static List<?> jsonToList(String jsonStr, java.lang.reflect.Type type) {  
        List<?> objList = null;  
        if (gson != null) {  
            objList = gson.fromJson(jsonStr, type);  
        }  
        return objList;  
    }  
  
    /** 
     * 将json格式转换成map对象 
     * @author fuyzh 
     * @param jsonStr 
     * @return 
     */  
    public static Map<?, ?> jsonToMap(String jsonStr) {  
        Map<?, ?> objMap = null;  
        if (gson != null) {  
            java.lang.reflect.Type type = new com.google.gson.reflect.TypeToken<Map<?, ?>>() {  
            }.getType();  
            objMap = gson.fromJson(jsonStr, type);  
        }  
        return objMap;  
    }  
  
    /** 
     * 将json转换成bean对象 
     * @author fuyzh 
     * @param jsonStr 
     * @return 
     */  
    public static Object jsonToBean(String jsonStr, Class<?> cl) {  
        Object obj = null;  
        if (gson != null) {  
            obj = gson.fromJson(jsonStr, cl);  
        }  
        return obj;  
    }  
  
    /** 
     * 将json转换成bean对象 
     * @author fuyzh 
     * @param jsonStr 
     * @param cl 
     * @return 
     */  
    @SuppressWarnings("unchecked")  
    public static <T> T jsonToBeanDateSerializer(String jsonStr, Class<T> cl,  
            final String pattern) {  
        Object obj = null;  
        gson = new GsonBuilder()  
                .registerTypeAdapter(Date.class, new JsonDeserializer<Date>() {  
                    public Date deserialize(JsonElement json, Type typeOfT,  
                            JsonDeserializationContext context)  
                            throws JsonParseException {  
                        SimpleDateFormat format = new SimpleDateFormat(pattern);  
                        String dateStr = json.getAsString();  
                        try {  
                            return format.parse(dateStr);  
                        } catch (ParseException e) {  
                            e.printStackTrace();  
                        }  
                        return null;  
                    }  
                }).setDateFormat(pattern).create();  
        if (gson != null) {  
            obj = gson.fromJson(jsonStr, cl);  
        }  
        return (T) obj;  
    }  
  
    /** 
     * 根据 
     * @author fuyzh 
     * @param jsonStr 
     * @param key 
     * @return 
     */  
    public static Object getJsonValue(String jsonStr, String key) {  
        Object rulsObj = null;  
        Map<?, ?> rulsMap = jsonToMap(jsonStr);  
        if (rulsMap != null && rulsMap.size() > 0) {  
            rulsObj = rulsMap.get(key);  
        }  
        return rulsObj;  
    }  
  
} 